Although resistance takes many forms, this article elucidates the primary source of resistance in psychotherapy as well as the fundamental resistance to leading a fulfilling life. The ultimate resistance to change, in both cases, originates in the anticipatory fear of arousing existential angst. To varying degrees, most individuals retreat from life and adopt defense mechanisms in an attempt to avoid reawakening suppressed feelings of terror and dread they experienced as children in early separation experiences, and, in particular, when they first learned about death. As clients dismantle their defenses during therapy and move toward increased individuation and self-fulfillment, these unconscious fears threaten to emerge into conscious awareness, and core resistances come into play. Certain events and circumstances, both positive and negative, arouse or intensify latent death anxiety, whereas other circumstances and defenses relieve it. There are numerous defenses that help ameliorate the core anxiety including the fantasy bond—an illusion of connection or fusion with another person, persons, groups, or causes—addictions, microsuicidal behavior, and literal and symbolic methods of denying one’s eventual demise. Although these defenses provide a measure of security and a sense of immortality, they adversely affect one’s psychological adjustment, emotional well-being, and interpersonal relationships.